Charging-induced implant operation

ABSTRACT

Presented herein are techniques for initiating a night-time mode of operation in an implantable hearing prosthesis in response to detection of night-time recharging operations. More specifically, an implantable hearing prosthesis comprises a rechargeable battery that is configured to be recharged via an external night-time charging device, such as a pillow charger. The implantable hearing prosthesis is configured to detect inductive charging of the rechargeable battery by the external night-time charging device. In response, the implantable hearing prosthesis is switched to a night-time mode of operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/678,379, filed on Aug. 16, 2017, the entire contents of which areincorporated by reference.

BACKGROUND Field of the Invention

The present invention relates generally to operations of an implantablemedical device that are induced by the initiation of implant charging.

Related Art

Medical devices having one or more implantable components, generallyreferred to herein as implantable medical devices, have provided a widerange of therapeutic benefits to recipients over recent decades. Inparticular, partially or fully-implantable medical devices such ashearing prostheses (e.g., bone conduction devices, mechanicalstimulators, cochlear implants, etc.), implantable pacemakers,defibrillators, functional electrical stimulation devices, and otherimplantable medical devices, have been successful in performinglifesaving and/or lifestyle enhancement functions for a number of years.

The types of implantable medical devices and the ranges of functionsperformed thereby have increased over the years. For example, manyimplantable medical devices now often include one or more instruments,apparatus, sensors, processors, controllers or other functionalmechanical or electrical components that are permanently or temporarilyimplanted in a recipient. These functional components perform diagnosis,prevention, monitoring, treatment or management of a disease or injuryor symptom thereof, or are employed to investigate, replace or modifythe anatomy or a physiological process. Many of these functionalcomponents utilize power and/or data received from external componentsthat are part of, or operate in conjunction with, the implantablemedical device.

SUMMARY

In one aspect a method performed at an implantable hearing prosthesiscomprising a rechargeable battery is provided. The method comprises:detecting inductive charging of the rechargeable battery by an externalnight-time charging device; and in response to detecting the inductivecharging of the rechargeable battery, switching the implantable hearingprosthesis to a night-time mode of operation.

In another aspect an implantable hearing prosthesis is provided. Theimplantable hearing prosthesis comprises: an implantable coil configuredto be inductively coupled to an external coil of an external night-timecharging device; an implantable rechargeable battery; and an implantcontroller configured to detect a charging cycle in which therechargeable battery is charged using signals received from the externalnight-time charging device, and, when the rechargeable battery ischarged using signals received from the external night-time chargingdevice, initiate a night-time mode of operation for the implantablehearing prosthesis.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described herein in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating a cochlear implant system, inaccordance with certain embodiments presented herein;

FIG. 2A is a schematic block diagram of a pillow charger, in accordancewith certain embodiments presented herein;

FIG. 2B is schematic block diagram of a cochlear implant, in accordancewith certain embodiments presented herein;

FIG. 3 is a schematic diagram of a portion of a cochlear implant, inaccordance with certain embodiments presented herein;

FIG. 4 is schematic block diagram of a cochlear implant, in accordancewith certain embodiments presented herein; and

FIG. 5 is a flowchart of a method, in accordance with certainembodiments presented herein.

DETAILED DESCRIPTION

Presented herein are techniques for initiating a night-time mode ofoperation in an implantable hearing prosthesis in response to detectionof night-time recharging operations. More specifically, an implantablehearing prosthesis comprises a rechargeable battery that is configuredto be recharged via an external night-time charging device, such as apillow charger. The implantable hearing prosthesis is configured todetect inductive charging of the rechargeable battery by the externalnight-time charging device. In response, the implantable hearingprosthesis is switched to a night-time mode of operation.

Merely for ease of illustration, the techniques presented herein areprimarily described with reference to one type of implantable medicaldevice, namely a cochlear implant. It is to be appreciated that thetechniques presented herein may be implemented by any other partially orfully implantable medical device now known or later developed, includingother implantable hearing prostheses, such as auditory brainstemstimulators, electro-acoustic hearing prostheses, bimodal hearingprostheses, etc., and/or other types of medical devices, such as painrelief implants, pacemakers, etc.

FIG. 1 is a block diagram of an exemplary system 101 that includes acochlear implant 100 in accordance with embodiments presented 100 and anexternal night-time charging device 103. The night-time charger 103 mayhave a number of different forms, such as a pillow charger, chargingmat, neck pillow, etc., but is generally a non-battery powered device(i.e., a device connected to mains electric power) configured to supplycharging power to an implantable medical device while the recipient ofthe medical device sleeps. For ease of description, embodiments areprimarily described herein with reference to the night-time charger 103as a pillow charger.

As described below, the cochlear implant 100 comprises a rechargeablebattery (not shown in FIG. 1) that is configured to be recharged usingpower signals received from the pillow charger 103 via an inductiveradio frequency (RF) link. Also as described below, the pillow charger103 is a device that includes one or more coil antennas that emits amagnetic field and which is arranged to be positioned in proximity to arecipient's head while he or she sleeps. Each of the coil antennas areformed by a plurality of “wire loops” or “windings” of electricalconductors. As described further below, the cochlear implant 100 isconfigured to detect inductive charging of the rechargeable battery bythe pillow charger 103 and, in response, switch the cochlear implant 100to a night-time mode of operation.

It is to be appreciated that the cochlear implant 100 of FIG. 1, as wellas the pillow charger 103 of FIG. 1, may each have a number of differentarrangements. FIG. 2A is a block diagram illustrating one examplearrangement for pillow charger 103, referred to as pillow charger 203,in accordance with embodiments presented herein. FIG. 2B is a blockdiagram illustrating one example arrangement for the cochlear implant100, referred to as cochlear implant 200.

Referring first to FIG. 2A, the pillow charger 203 comprises a coilexcitation system 248, sometimes referred to herein as a coil excitationsystem, and one or more coil antennas 250 that emit a magnetic field.For ease of description, pillow chargers in accordance with embodimentspresented herein are primarily described with reference to the use of asingle coil antenna. However, it is to be appreciated that pillowchargers in accordance with embodiments presented herein may include aplurality of coil antennas.

In the embodiment of FIG. 2B, the coil antenna 250 is formed by aplurality of “loops” or “coils” 252 of wire, where the plurality ofloops are sometimes collectively referred as a “wire-loop bundle.” Thepillow charger 203 also comprises an electrical connection 254 to apower source. In one example, the electrical connection includes agalvanic isolation element or a transformer (not shown in FIG. 2A) toinsulate the power source from the electronics of the pillow charger203. The electrical connection 254 may also include a 12V DC adapter(not shown in FIG. 2A).

The coil excitation system 248 comprises one or more elements (e.g., awaveform generator, one or more amplifiers, tuning capacitors, etc.)that are used to drive the coil antenna 250 with an alternating currentsignal so that the coil antenna 250 will emit a corresponding magneticfield. That is, when driven by the coil excitation system 248, the wirecoils 252 hold varying electrical currents that generate/emit magneticfields that, as described further below, can be used to inductivelycharge the cochlear implant 200 (FIG. 2B).

Referring next to FIG. 2B, the cochlear implant 200 is a totallyimplantable cochlear implant where all components of the cochlearimplant are configured to be implanted under the skin/tissue 205 of arecipient. Because all components are implantable, cochlear implant 200operates, for at least a finite period of time, without the presence ofan external device (e.g., without pillow charger 203).

Cochlear implant 200 includes an implant body (main module) 210, a leadregion 214, and an elongate intra-cochlear stimulating assembly 216. Theimplant body 210 generally comprises a hermetically-sealed housing 218in which a stimulator unit (stimulation electronics) 222, a soundprocessor 224, a memory 225, an implant controller 226 (i.e., batteryand power management component or battery processor), RF interfacecircuitry 228, and a rechargeable battery 230 are disposed. It is to beappreciated that cochlear implant 200 may include one or more othercomponents that, for ease of illustration, have been omitted from FIG.2B.

The implant body 210 also includes one or more implantable sound inputs,such as microphones, accelerometers, etc. 212 and aninternal/implantable coil 232 that are each typically located externalto the housing 218. The implantable coil 232 is connected to elementswithin the housing 218 via hermetic feedthroughs (not shown in FIG. 2).Implantable coil 232 is typically a wire antenna coil comprised ofmultiple turns of electrically insulated single-strand or multi-strandplatinum or gold wire. The electrical insulation of implantable coil 232is provided by a flexible molding (e.g., silicone molding), which is notshown in FIG. 2A. Generally, a magnet is fixed relative to theimplantable coil 232 for magnetic coupling with a magnet in an externaldevice.

Elongate stimulating assembly 216 is configured to be at least partiallyimplanted in the recipient's cochlea (not shown) and includes aplurality of longitudinally spaced intra-cochlear electrical stimulatingcontacts (electrodes) 234 that collectively form a contact array 236 fordelivery of electrical stimulation (current) to the recipient's cochlea.Stimulating assembly 216 extends through an opening in the cochlea(e.g., cochleostomy, the round window, etc.) and has a proximal endconnected to the stimulator unit 222 via the lead region 214 and ahermetic feedthrough (not shown in FIG. 2B). Lead region 214 includesone or more conductors (wires) that electrically couple the electrodes234 to the stimulator unit 222. In this way, cochlear implant 200electrically stimulates the recipient's auditory nerve cells, bypassingabsent or defective hair cells that normally transduce acousticvibrations into neural activity, in a manner that causes the recipientto perceive one or more components of the received sound signals.

The one or more implantable sound inputs 212 are configured todetect/receive input sound signals that are provided to the soundprocessor 224 by the RF interface circuitry 228. The sound processor 224is configured to execute sound processing and coding to convert thereceived sound signals into output signals for use by the stimulatorunit 222 in delivering electrical stimulation (current) to the recipientvia electrodes 234.

The implantable coil 232 enables cochlear implant 200 to inductivelyreceive power/current signals from a pillow charger (e.g., pillowcharger 203) via an RF link, sometimes referred to herein as aninductive power link, which is represented in FIG. 2B by arrow 242. Thatis, as noted above with reference to FIG. 2A, when driven by the coilexcitation system 248, the wire coils 252 of the coil antenna 250 holdvarying electrical currents that generate/emit magnetic fields. When theimplantable coil 232 is placed in proximity to the coil antenna 250 ofthe pillow charger 203 (FIG. 2A), the magnetic fields emitted by thecoil antenna 250 pass through the implantable coil 232 and, as a result,a current is induced in the implantable coil 232. The RF interfacecircuitry 228 is configured to operate under the control of the implantcontroller 226 and contains the necessary switches so as to charge therechargeable battery 230 using the power received via the inductivepower link 242 (i.e., the rechargeable battery 232 is inductivelycharged by the pillow charger 202). The rechargeable battery 230 isconfigured to store sufficient energy needed to power the other elementsof the cochlear implant 200, as well as to provide the current needed toelectrically stimulate the recipient's cochlea.

The total amount of energy a battery can store at any one time, oftenmeasured in terms of Milliampere Hours (mAh), is referred to herein asthe “capacity” of the battery. It is generally assumed that a recipienthas the ability to charge his/her rechargeable battery at night and, assuch, the goal is to provide a recipient with approximately one full dayof operation on a single battery charge (i.e., a fully charged batteryshould power the cochlear implant for at least approximately 14-16 hourswithout the need to recharge the battery). As such, pillow charger 203is a device that is used to inductively charge rechargeable battery 230while the recipient is asleep (e.g., during the night). In accordancewith embodiments presented herein, the typical use of night-timechargers, such as pillow charger 203, while a recipient is asleep isleveraged to activate a secondary mode of operation of a cochlearimplant, sometimes referred to herein as a “night-time” mode.

More specifically, in the embodiment of FIG. 2B, the implant controller226 is configured to detect inductive charging of the rechargeablebattery 230 (e.g., detect the initiation/beginning of a battery chargingcycle). In response to detecting the inductive charging, the implantcontroller 226 is configured to switch the cochlear implant 200 to anight-time mode of operation. As such, in accordance with embodimentspresented herein, the cochlear implant 200 has at least two distinctmodes of operation, namely a “primary” mode of operation that isactivated when the cochlear implant 200 is not being charged by pillowcharger 203 and the secondary or “night-time” mode of operation that isonly activated in response to detection of inductive charging of therechargeable battery 230 by pillow charger 203. Although the secondarymode of operation of cochlear implant 200 is described as being a“night-time” mode, it is to be appreciated that this mode may also oralternatively be activated at different times of the day. In general,the “night-mode” is used to refer to a mode of operation that istriggered when the rechargeable battery 230 is being inductive chargedby the pillow charger 203.

In the primary mode of operation, the implant controller 226 causes thecochlear implant 200 to operate in accordance with a first set ofsettings (e.g., clinically determined settings) that enable the cochlearimplant to detect acoustic sound signals and to evoke perception ofthose acoustic sound signals. In contrast, in the night-mode ofoperation of the cochlear implant 200, the implant controller 226 causesthe cochlear implant 200 to operate in accordance with a second set ofsettings that are specifically tailored to a sleeping recipient (e.g.,reduce power consumption and/or to provide extra functionality/therapythat is useful at night like tinnitus suppression signals, fire alarmdetection, wake-up signals, sleep inducing sounds, etc.)

The second set of settings that are activated during the night-mode ofoperation may be take a number of different forms. In one embodiment,the second set of settings form a “reduced-sensitivity sound processingprogram” in which the cochlear implant 200 intentionallyeliminates/omits, from delivery to the recipient, sounds with certainattributes so as to minimize disturbances to the recipient while therecipient is sleeping. That is, while executing the reduced-sensitivitysound processing program, the cochlear implant 200 processes sounds in amanner that intentionally reduces the functionality of the implant. Thistype of operation is different from the processing that is executed inthe primary mode of operation where, in general, the cochlear implant200 attempts to maximize sound understanding (i.e., the cochlear implant200 processes the signals coming from the implantable microphone andturns this into stimulation pulses inside the cochlea to provide speechunderstanding).

For example, in accordance with one reduced-sensitivity sound processingprogram, the sound processor 224 is configured to prevent, from beingdelivered to the recipient, acoustic sounds that have an amplitude thatis below a predetermined threshold level. This may be implemented byraising an acoustic hearing threshold that is used by the soundprocessor 224 during the night-time mode relative to an acoustic hearingthreshold using during the primary mode (i.e., the implant controller226 increasing the minimum acoustic amplitude that is needed to triggerdelivery of stimulation to the recipient).

In the same or other reduced-sensitivity sound processing program, thesound processor 224 is also or alternatively configured to prevent, frombeing delivered to the recipient, acoustic sounds that have an amplitudethat is above a predetermined comfort level. This may be implemented bydropping any sound signals that have an acoustic amplitude greater thana predetermined upper threshold level.

In certain such embodiments, the determination of whether to drop soundsignals that exceed the predetermined upper threshold level isaccompanied by a secondary determination relating to temporal aspects ofthe sound. That is, the sound processor 224 may be configured to preventacoustic sounds from being delivered to the recipient only when: (1) theacoustic amplitude is greater than the predetermined upper level, and(2) when the acoustic sounds are associated with predetermined temporalcharacteristics. For example, the sound processor 224 may eliminate highamplitude acoustic sounds that also have a time length that is less thana predetermined threshold, are not repeated within a predetermined timeperiod, etc. The sound processor 224 may also be configured to monitorfor key danger words (e.g., “FIRE,” “HELP,” “MOM,” “DAD,” etc.) andallow those sounds to be delivered to the recipient regardless of thesound level, temporal characteristics, etc.

In another embodiment, the second set of settings form a “reduced-powerconsumption sound processing program” in which the implant controller226 intentionally reduces the functionality of the cochlear implant 200to conserve power. That is, the cochlear implant 200 generally operatesdifferently from that implemented in the primary mode of operation in amanner that intentionally reduces the functionality of the implant. Morespecifically, in certain reduced-power consumption sound processingprograms the implant controller 226 is configured to reduce thenumber/amount of current pulses that are stimulated inside the cochlea.For example, where a typical primary (day-time) program might stimulatethe cochlea at a certain rate (e.g., 7000 pulses per second), areduced-power consumption sound processing program might reduce thestimulation rate to predetermined upper limit (e.g., 3500 pulses persecond). In certain examples, stimulation pulses may be delivered up tothe upper limit and only started again when needed (e.g., during a firealarm).

In other reduced-power consumption sound processing programs the implantcontroller 226 is configured to reduce the clock rate used by the soundprocessor 224. For example, where a typical primary (day-time) programmay run on a 20 MHz clock, a reduced-power consumption sound processingprogram might reduce the clock to 10 MHz or 5 MHz at night.

Another alternative for a reduced-power consumption sound processingprogram is to disable certain elements of the cochlear implant 200. Forexample, the sound processor 224 may be formed by a plurality (e.g., 6)Digital Signal Processors (DSPs) which all may be simultaneously enabledduring a typical primary (day-time) program. During a reduced-powerconsumption sound processing program, several of the DSPs could bedisabled and only activated if/when needed.

In another embodiment, the second set of settings include a “tinnitusmasking program” in which tinnitus masking signals are delivered to therecipient. For example, in accordance with one illustrative tinnitusmasking program, the implant controller 226 is configured to initiatethe delivery of tinnitus masking signals to the recipient for at least aperiod of time (e.g., a predetermined period of time). The tinnitusmasking signals can have different shapes and forms (e.g., a pure sineat a certain frequency, the sound of the sea, white noise, music, etc.).In general, a tinnitus masker may be a “tone-generator” inside soundprocessor 224, a prerecorded sample that is read from memory 225, etc.

In certain tinnitus masking programs, the tinnitus masking signals maybe delivered to the recipient continuously/periodically the entire timethat the cochlear implant 200 operations in the night-time mode. Inother tinnitus masking programs, the tinnitus masking signals may onlybe delivered for limited periods of time (e.g., 1 hour, 2 hours, etc.).For example, tinnitus may be most problematic while the recipient isattempting to fall asleep. As such, the tinnitus masking signals may bedelivered for a time period that is sufficient for the recipient to fallasleep and, thereafter, the tinnitus masking signals are no longerdelivered (e.g., to reduce power consumption). In still other tinnitusmasking programs, the tinnitus masking signals may be delivered untilthe implant controller 226 determines that the recipient has fallenasleep. This determination may be made based on, for example, inputsfrom an implantable accelerometer or other sensor.

As noted, in certain embodiments, the sound processor 224 uses atinnitus mask stored in the memory 225 to generate the tinnitus maskingsignals. In other embodiments, the tinnitus masking signals aregenerated in real-time by the sound processor 224 (i.e., a tonegenerator as part of a DSP). In one such embodiment, the sound processor224 uses the time-varying current in the implantable coil 232 is used toat least partially or pseudo-randomize the tinnitus masking signal. Thiscould be implemented in a number of manners, such as using the leastsignificant bit) (LSB) of the incoming signal, etc.

In certain embodiments, the parameters utilized in a selected night-timemode are stored in memory 225. However, in other embodiments, the pillowcharger 203 can communicate some parameters (e.g., via load modulationor a separate data link) to the cochlear implant 200.

As noted above, the implant controller 226 is configured to initiate thenight-time mode in response to detecting inductive charging of therechargeable battery 230 by the pillow charger 203. The implantcontroller 226 can be configured to detect the inductive charging in anumber of different manners.

In one embodiment, the implant controller 226 is configured to detectthe inductive charging of the rechargeable battery 230 based on thecurrent that is supplied to the rechargeable battery. FIG. 3 is asimplified schematic diagram illustrating one such arrangement where acochlear implant 300 includes, among other elements, an implantable coil332, RF interface circuitry 328, a rechargeable battery 330, and animplant controller 326, all of which may be implemented as describedabove with reference to FIG. 2B. For ease of illustration, otherelements of the cochlear implant 300 have been omitted from FIG. 3.

In the example of FIG. 3, a current sense circuit 360 is located betweenthe RF interface circuitry 328 and the input (positive terminal) 331 ofthe rechargeable battery 330. In this illustrative embodiment, thecurrent sense circuit 360 comprises a sense resistor 361 and anamplifier 362. In general, the current sense circuit 360 provides theimplant controller 326 with an input (e.g., measurement) indicating, forexample, the level/magnitude of the current that is provided to therechargeable battery 330 (i.e., a measure of the instantaneous chargingcurrent for the battery). Based on the input (e.g., currentmeasurement), the implant controller 326 can determine when charging ofthe rechargeable battery 330 has been, for example, initiated,completed, etc. For example, the implant controller 326 may detect whenthe current that is provided to the rechargeable battery 330 increases(e.g., above a predetermined threshold), indicating that therechargeable battery 330 is receiving a charging current from a pillowcharger charger. As a result, the implant controller 326 can initiate anight-time mode of operation, as described above.

It is to be appreciated the current sense circuit 360 of FIG. 3 isillustrative and that other implementations for current sense circuitsor for detecting inductive charging of the rechargeable battery based onthe current that is supplied to the rechargeable battery are within thescope of the present invention. It is also to be appreciated that animplantable medical device in accordance with embodiments presentedherein may detect inductive charging of a rechargeable battery usingother techniques.

For example, returning to the specific arrangements of FIGS. 2A and 2B,the implant controller 226 may be configured to detect inductivecharging of the rechargeable battery 230 using information obtained fromthe inductive power link 242. The coil antenna 250 (FIG. 2A) of thepillow charger 203 and the implantable coil 232 are closely coupled toone another and the coil antenna 250 transmits a continuous time-varyingRF carrier signal (i.e., wave). That is, a continuous time-varying RFcarrier signal forms a basis of the inductive power link 242 and is usedto transfer power to the cochlear implant 200. In accordance withcertain embodiments presented herein, the pillow charger 203 isconfigured to use this inductive coupling to signal to the cochlearimplant 200 that charging of the rechargeable battery 230 is going tobe, and/or has been, initiated.

More specifically, in one such example, the pillow charger 203 isconfigured to alter/adjust one or more characteristics of the coilexcitation system 248 in accordance with a predeterminedpattern/sequence which, due to the coupling between the coil antenna 250and the implantable coil 232, causes a corresponding predeterminedpattern/sequence of impedance changes (referred sometimes as reflectedload) at the implantable coil 232 (e.g., change of the load at theimplantable coil 232 sensed by an implantable coil impedance sensor).This impedance/load change sensed at the implantable coil 232 affectsthe amount of current flowing through the implantable coil 232 and thesequence of load changes is detectable via current changes at theimplantable coil 232.

Detection of the predetermined pattern/sequence of impedance changes atthe implantable coil 232 signals to the implant controller 226 theinitiation of charging of the rechargeable battery 230 (i.e., that abattery charging cycle is beginning or is about to begin). As a result,when the predetermined pattern/sequence of impedance changes isdetected, the implant controller 226 can initiate a night-time mode ofoperation, as described above.

As noted above, in certain embodiments presented herein the pillowcharger 203 can utilize load modulation of the inductive power link 242to signal to the implant controller 226 the initiation of charging ofthe rechargeable battery 230. In other embodiments, the pillow charger203 can utilize on-off keying to signal the initiation of charging ofthe rechargeable battery 230. More specifically, when initiationcharging, the pillow charger 203 could turn the time-varying RF carriersignal on and off in accordance with a predetermined sequence/pattern(e.g., alternatively turn the RF carrier signal on five times and offfive times). This on-off keying sequence is detectable by a sensor inthe cochlear implant 200. As a result, when the predetermined on-offkeying sequence is detected, the implant controller 226 can initiate anight-time mode of operation, as described above.

In further embodiments, the implant controller 226 may determine thatcharging of the rechargeable battery 230 has been initiated based on avoltage measured at the implantable coil 232. For example, in certainembodiments the pillow charger 203 may induce a characteristic voltageand/or a characteristic voltage pattern at the implantable coil 232 whenproviding charging power to the cochlear implant. When thecharacteristic voltage and/or a characteristic voltage pattern at isdetected by the implant controller 226 (e.g., via a sensor coupled tothe implantable coil 232), the implant controller 226 can initiate anight-time mode of operation, as described above. The characteristicvoltage and/or a characteristic voltage pattern can take a number ofdifferent forms. In one example, the pattern could be 100 ms on, 100 msoff, 200 ms on, 200 ms off, 100 ms on, 100 ms off. Further examples ofcharacteristic voltage and/or a characteristic voltage patternsgenerated by a pillow charger, and which may be detected at animplantable coil and implant controller, are described in commonly-ownedand co-pending U.S. patent application Ser. No. 15/454,405, filed onMar. 9, 2017, the content of which is hereby incorporated by referenceherein.

In certain embodiments, cochlear implant 200 is coupled to a pillowcharger that includes multiple coil antennas each configured to emit amagnetic field. In these embodiments, the pillow charger is configuredto shift the phase, amplitude, and/or other characteristics of one ormore of the emitted magnetic fields. By varying at least onecharacteristic of the emitted magnetic fields relative to one another(i.e., varying the relative phase and/or relative amplitude differencesbetween the emitted magnetic fields), the direction/orientation of thecombined magnetic field vector also changes (e.g., rotates) over time.As a result, regardless of the relative locations of the multiple coilantennas and the implantable coil 232, the implantable coil 232 will, atdifferent times, have different amounts of magnetic flux there throughthat induces a current in the implantable coil. In these embodiments,the variation in the magnetic flux through the implantable coil 232 isdetected by the implant controller 226 (e.g., via a sensor coupled tothe implantable coil 232), and the implant controller 226 can initiate anight-time mode of operation, as described above.

FIG. 2B illustrates an example sensor 264 that may be included incochlear implant 200 to monitor one or more characteristics of theinductive power link 242 and/or the implantable coil 232 (e.g., loadchanges, on-off keying, voltage, etc.) for use by the implant controller226. The sensor 264 is shown using dashed lines to indicate that the useof the sensor 264 is illustrative of the embodiments described above.

In the above embodiments, no additional communication between the pillowcharger 203 and the cochlear implant 200, beyond the inductive powerlink 242, is needed for the implant controller 226 to detect initiationof charging of the rechargeable battery 230 (i.e. the pillow charger 203operates in an “open-loop” configuration without feedback from thecochlear implant). However, in certain arrangements, the cochlearimplant 200 and the pillow charger 203 cane be configured to communicatewith one another via a separate data link. For example, the cochlearimplant 200 and the pillow charger 203 may each be configured with awireless short range transceiver (e.g., a Bluetooth® transceiver, aBluetooth® Low Energy (BLE) transceiver, etc.) for direct communicationwith one another. Bluetooth® is a registered trademark owned byBluetooth SIG, Inc. That is, a separate communication/data link may beprovided between the cochlear implant 200 and the pillow charger 203(i.e., running in parallel with the inductive power link 242) and thisseparate data link can be used by the pillow charger 203 to inform thecochlear implant 200 that charging of the rechargeable battery 230 hasbeen, or is going to be, initiated.

FIG. 4 is a simplified block diagram of a pillow charger 403 and acochlear implant 400 configured to communicate with one another via theinductive power link 242 and a separate wireless data link 465. Pillowcharger 403 is similar to pillow charger 203 of FIG. 2A and comprisesthe coil excitation system 248 and the coil antenna 250. Pillow charger403 also comprises a wireless transceiver 470.

Cochlear implant 400 is similar to cochlear implant 200 of FIG. 2B andcomprises the implantable sound inputs(s) 212, the sound processor 224,the implantable coil 232, the memory 225, the implant controller 226,the RF interface circuitry 228, the rechargeable battery 230, thestimulator unit 222, the implant controller 226, and the stimulatingassembly 236. Cochlear implant 400 also comprises a wireless transceiver472.

The wireless transceivers 470 and 472 are each configured in accordancewith one or more wireless technology standards and are configured toexchange data over a short distance (e.g., using short-wavelength Ultrahigh frequency (UHF) radio waves in one or more industrial, scientificand medical (ISM) radio bands, such as the ISM band from 2.4 to 2.485GHz). That is, the wireless transceivers 470 and 472 provide thewireless data link 465.

Embodiments have generally been described above with reference todifferent primary (single factor) determinations for detection of pillowcharging operations (i.e., for detecting the charging of an implantablerechargeable battery). It is to be appreciated that certain embodimentspresented herein may combine the above determinations to detectinductive charging of an implantable rechargeable battery. That is, itis to be appreciated that the different determinations described aboveare illustrative and that other determinations may be used in accordancewith embodiments presented herein. It is also to be appreciated that theabove determinations are not mutually exclusive and that multipledeterminations may be used together.

It is also to be appreciated that certain embodiments presented hereinmay also make use one or more additional “secondary” inputs to confirmthat the cochlear implant is coupled to a night-time charger and,accordingly, to confirm whether the night-time mode of operation shouldbe initiated. In certain examples, these secondary inputs may do notrelate to whether the rechargeable battery is being charged, but insteadrelate to ancillary factors. The secondary inputs are used to ensurethat the night-time mode is not initiated when the cochlear implant isreceiving charging power from another type of external charger, such asa body worn charger, a chair-based charger, etc. For ease ofillustration, secondary inputs for use in confirming whether thenight-time mode should be initiated are described with reference to thearrangements of FIGS. 2A and 2B and are combined with one or more of theother determinations for detection of pillow charging operationsdescribed elsewhere herein.

In one embodiment, the secondary input used to determine whether thenight-time mode should be initiated is the time that has elapsed sincethe last battery charging cycle (e.g., the time since the most recentprevious battery charging cycle was initiated, the time since the mostrecent previous battery charging cycle ended, etc.). As noted above, anight-time charger, such as pillow charger 203, is generally used eachnight while the recipient is asleep. As a result, the relative timingbetween the most recent charging cycles could be used by the implantcontroller 226 to differentiate between different types of chargers,reflected in the relative usage timings. For example, detection of a newcharging cycle 20-24 hours after the beginning of the most recentprevious pillow charger-based charging cycle may indicate that thebattery is one again being charged by the pillow charger 203.

In these embodiments, the implant controller 226 is configured to trackthe timing of charging cycles (e.g., via an embedded timer). In certainembodiments, the relative timing between charging cycles may be analyzedin view of the current time-of-day (ToD) to differentiate betweendifferent types of chargers and, accordingly, to confirm whether thenight-time mode of operation should be initiated. In other embodiments,the secondary input used to determine whether the night-time mode shouldbe initiated is the time-of-day only (i.e., without reliance on therelative timing between the most recent charging cycles).

In another embodiment, the secondary input used to determine whether thenight-time mode of operation should be initiated is the acousticscene/environment. In these embodiments, the sound processor 224 or theimplant controller 226 is configured to evaluate/analyze received soundsignals to determine the primary or main sound “class” of the soundsignals (i.e., determine the environment in which the cochlear implantis currently/presently located). That is, the sound processor 224 or theimplant controller 226 is configured to use the received sound signalsto “classify” the ambient sound environment of the cochlear implant 200and/or the sound signals into one or more sound categories (i.e.,determine the input signal type). The sound classes/categories mayinclude, but are not limited to, “Speech,” “Noise,” “Speech+Noise,”“Music,” and “Quiet.” Using the determined class, the implant controller226 is configured to determine whether the rechargeable battery 230 isreceiving power from pillow charger 203 or some other type of chargerand accordingly, to confirm whether the night-time mode of operationshould be initiated.

For example, if the rechargeable battery 230 is receiving power and itis determined that the cochlear implant 200 is in a “Noise” environment,then the implant controller 226 may determine that the implantrechargeable battery 230 is receiving power from a charger other thanthe pillow charger 203 (e.g., the recipient is watching television andis receiving power from a chair-based charger). As a result, it may beundesirable to activate the night-time mode. Conversely, if therechargeable battery 230 is receiving power and it is determined thatthe cochlear implant 200 is in a “Quiet” environment, then the implantcontroller 226 may determine that the implant rechargeable battery 230is in receiving power from the pillow charger 203. As such, the implantcontroller 226 may initiate the night-time mode.

In another embodiment, the secondary input used to determine whether thenight-time mode of operation should be initiated is the output of anaccelerometer or other sensor that is used to track, for example, theorientation of the recipient's head. Using the input from this type ofsensor, the implant controller 226 could determine whether the recipientis laying down and, as such, likely receiving power from a night-timecharger. FIG. 2B illustrates an example accelerometer 265 that may beincluded in cochlear implant 200. The accelerometer 265 is shown usingdashed lines to indicate that the use of accelerometer 265 isillustrative of the embodiments described above.

In a further embodiment, the cochlear implant 200 is configured tomonitor, for example, the recipient's heartrate, breathing rate, etc.and these attributes may be used as the secondary input used. In certainexamples, the recipient's heartrate, breathing rate, etc. could betracked using the implantable sound inputs 212 and analyzed to determinewhen the recipient is likely falling asleep and, as such, when thenight-time mode should be activated.

It is to be appreciated that the different secondary inputs describedabove are illustrative and that other secondary inputs may be used inaccordance with embodiments presented herein. It is also to beappreciated that the secondary inputs are not mutually exclusive andthat multiple secondary inputs may be used together to confirm whetherthe night-time mode should be initiated.

FIG. 5 is a flowchart of a method 580 performed at an implantablehearing prosthesis comprising a rechargeable battery, in accordance withembodiments presented herein. Method 580 begins at 582 where theimplantable hearing prosthesis detects inductive charging of therechargeable battery by an external night-time charging device. At 584,in response to detecting the inductive charging, the implantable hearingprosthesis is switched to a night-time mode of operation. In oneembodiment, switching to the night-time mode of operation includesdelivery of tinnitus masking signals to the recipient for at least aperiod of time. In the same or other embodiments, switching to thenight-time mode of operation includes initiating a reduced-sensitivitysound processing program. In the same or other embodiments, switching tothe night-time mode of operation includes initiating a reduced-powerconsumption sound processing program.

It is to be appreciated that the embodiments presented herein are notmutually exclusive.

The invention described and claimed herein is not to be limited in scopeby the specific preferred embodiments herein disclosed, since theseembodiments are intended as illustrations, and not limitations, ofseveral aspects of the invention. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the invention in addition to those shown and describedherein will become apparent to those skilled in the art from theforegoing description. Such modifications are also intended to fallwithin the scope of the appended claims.

What is claimed is:
 1. A method, comprising: at an implantable hearingprosthesis comprising a rechargeable battery and an implantable coil:receiving, via the implantable coil, inductive charging signalstransmitted by an external coil of an external night-time chargingdevice to the implantable coil via an inductive link; determining, basedon the inductive charging signals received at the implantable coil, thatthe rechargeable battery is being charged by the external night-timecharging device; and in response to determining that the rechargeablebattery is being charged, switching the implantable hearing prosthesisto a night-time mode of operation.
 2. The method of claim 1, whereindetermining, based on the inductive charging signals received at theimplantable coil, that the rechargeable battery is being charged by anexternal night-time charging device comprises: monitoring currentprovided from the implantable coil to the rechargeable battery to detectthe beginning of a battery charging cycle.
 3. The method of claim 1,wherein determining, based on the inductive charging signals received atthe implantable coil, that the rechargeable battery is being charged bythe external night-time charging device comprises: detecting, at theimplantable hearing prosthesis, a predetermined pattern of loadmodulation of the inductive link.
 4. The method of claim 1, whereindetermining, based on the inductive charging signals received at theimplantable coil, that the rechargeable battery is being charged by theexternal night-time charging device comprises: detecting, at theimplantable hearing prosthesis, a predetermined on-off keying pattern ofthe inductive power link.
 5. The method of claim 1, wherein determining,based on the inductive charging signals received at the implantablecoil, that the rechargeable battery is being charged by the externalnight-time charging device comprises: detecting, at the implantablehearing prosthesis, a predetermined voltage pattern at the implantablecoil.
 6. The method of claim 1, further comprising: receiving, via asecondary wireless communication link, a charging initiationnotification from the external night-time charging device.
 7. The methodof claim 1, wherein switching the implantable hearing prosthesis to anight-time mode of operation comprises: delivering tinnitus maskingsignals to the recipient for at least a period of time.
 8. The method ofclaim 7, wherein the external night-time charging device and theimplantable hearing prosthesis comprise an external coil and animplantable coil, respectively, that are coupled to one another via aninductive power link that uses a magnetic field to induce time-varyingcurrent in the implantable coil, and wherein the method furthercomprises: using the time-varying current in the implantable coil to atleast partially randomize the tinnitus masking signals.
 9. The method ofclaim 1, wherein switching the implantable hearing prosthesis to anight-time mode of operation comprises: initiating a reduced-sensitivitysound processing program.
 10. The method of claim 1, wherein switchingthe implantable hearing prosthesis to a night-time mode of operationcomprises: initiating a reduced-power consumption sound processingprogram.
 11. The method of claim 1, wherein detecting initiation ofinductive charging of the rechargeable battery by an external night-timecharging device comprises: confirming, based on one or more secondaryinputs, that the inductive charging is initiated by the externalnight-time charging device.
 12. The method of claim 11, wherein the oneor more secondary inputs comprise at least one of a time-of-day or arelative period of time since a previous battery charging cycle.
 13. Themethod of claim 11, wherein the one or more secondary inputs comprise adetermined sound class of the ambient sound environment of the hearingprosthesis.
 14. An implantable hearing prosthesis, comprising: animplantable coil configured to be inductively coupled to an externalcoil of an external night-time charging device to form an inductive linkover which the implantable coil receives inductive charging signals; animplantable rechargeable battery; and an implant controller configuredto determine, based on the inductive charging signals received at theimplantable coil, that the rechargeable battery is being charged by theinductive charging signals received from the external night-timecharging device, and, in response to determining that the rechargeablebattery is being charged, initiate a night-time mode of operation forthe implantable hearing prosthesis.
 15. The implantable hearingprosthesis of claim 14, further comprising: a current sense circuitconfigured to monitor current provided to the rechargeable battery andto generate an output representative of the current, wherein the implantcontroller is configured to determine, based on the output of thecurrent sense circuit, a beginning of a battery charging cycle.
 16. Theimplantable hearing prosthesis of claim 14, wherein to determine, basedon the inductive charging signals received at the implantable coil, thatthe rechargeable battery is being charged by the inductive chargingsignals received from the external night-time charging device, theimplant controller is configured to: monitor the inductive power linkfor a predetermined load modulation pattern indicating initiation of abattery charging cycle.
 17. The implantable hearing prosthesis of claim14, wherein to determine, based on the inductive charging signalsreceived at the implantable coil, that the rechargeable battery is beingcharged by the inductive charging signals received from the externalnight-time charging device, the implant controller is configured to:monitor the inductive power link for a predetermined on-off keyingpattern indicating initiation of a battery charging cycle.
 18. Theimplantable hearing prosthesis of claim 14, wherein to determine, basedon the inductive charging signals received at the implantable coil, thatthe rechargeable battery is being charged by the inductive chargingsignals received from the external night-time charging device, theimplant controller is configured to: monitor the inductive power linkfor a predetermined voltage pattern indicating initiation of a batterycharging cycle.
 19. The implantable hearing prosthesis of claim 14,further comprising: a wireless transceiver configured to receivenotifications from the external night-time charging device.
 20. Theimplantable hearing prosthesis of claim 14, wherein to initiate anight-time mode of operation for the implantable hearing prosthesis, theimplant controller is configured to: initiate delivery of tinnitusmasking signals to the recipient for at least a period of time.
 21. Theimplantable hearing prosthesis of claim 14, wherein to initiate anight-time mode of operation for the implantable hearing prosthesis, theimplant controller is configured to: initiate a reduced-sensitivitysound processing program.
 22. The implantable hearing prosthesis ofclaim 14, wherein to initiate a night-time mode of operation for theimplantable hearing prosthesis, the implant controller is configured to:initiate a reduced-power consumption sound processing program.
 23. Theimplantable hearing prosthesis of claim 14, wherein prior to initiatingthe night-time mode of operation, the implant controller is configuredto confirm, based on one or more secondary inputs, that the inductivecharging is initiated by the external night-time charging device. 24.The implantable hearing prosthesis of claim 23, wherein the one or moresecondary inputs comprise at least one of a time-of-day or a relativeperiod of time since a previous battery charging cycle.
 25. Theimplantable hearing prosthesis of claim 23 wherein the one or moresecondary inputs comprise a determined sound class of the ambient soundenvironment of the hearing prosthesis.